The present invention relates generally to electronic integrator circuits, and more specifically to a passive, i.e. unpowered, cylindrical integrator assembly.
Electronic integrator circuits are devices which produce an electronic output signal which is proportional to the time integral of the input signals that they receive. Such devices have applications in various basic and applied research fields, including pulsed-power microwave and laser source development, accelerator and plasma physics, electron beam propagation, inertial confinement and magnetic fusion, testing of advanced related nuclear weapons development, and other activities. In such applications, the integrator circuit approximates the mathematical process of integration of the input voltage.
It is often desired to integrate a signal from a previous time, (t-T), to the present time, t, in order to compensate for the time differentiation introduced by certain classes of sensors, including electric and magnetic field sensors. This previously has been done by using integrators which are only poor approximations particularly at GHz frequencies, to the actual desired mathematical integral. An integrator circuit generally consists of the charging of a capacitor through a series resistor, with the integrator output measured as the instantaneous voltage across the capacitor.
The prior art integrators, as described above, are often limited by their output risetimes, and some require external sources of power. The task of providing a passive integrator assembly with improved output voltage risetime characteristics is alleviated, to some extent, by the systems disclosed in the following U.S. Patents, the disclosures of which are incorporated herein by reference:
U.S. Pat. No. 3,500,257 issued to Mensa; PA0 U.S. Pat. No. 4,229,700 issued to Greene; and PA0 U.S. Pat. No. 4,586,008 issued to Raleigh.
The patent to Mensa teaches a passive RC integrator circuit which provides a linear output by adding a potentiometer in cascade across the RC input circuit. The patent to Green teaches a pulse width pulser having a 10 picosecond rise and fall time which employs a reed switch between a center conductor and the output line. The patent to Raleigh teaches a fast passive integrator device (250 picoseconds) which is in essence a low impedance coaxial transmission line.
While the references cited above represent definite advances in the art, the need for new integrator systems with improved risetimes represents an ongoing need particularly with a wide variety of measuring devices, or "diagnostics", utilized in many research fields. While some diagnostics produce an output voltage directly proportional to the quantity of interest, other diagnostics produce an electrical signal which is differentiating, or in other words, the output voltage is proportional to the time derivative of the quantity which is actually sought. This is particularly true Of the magnetic and electric field sensors commonly used in various basic and applied research fields, including pulsed power, microwave, and laser source development, accelerator and plasma physics, electron beam propagation, inertial confinement and magnetic fusion, plasma physics, electron beam propagation, inertial confinement and magnetic fusion, and testing of advanced concepts related to nuclear weapons development Instrumentation has an upper bound to its frequency bandpass The inherent characteristic of differentiating sensors to emphasize higher harmonic content implies that no matter what type of recording instrumentation is utilized, there will always be more high frequency distortion introduced by the recording system when it stores a differential signal relative to when it stores an undifferentiated, i.e., integrated, signal. Thus, the use of passive integrators with improved risetimes represents an ongoing need. The present invention is directed towards satisfying that need.